I think it's better to carefully and tell the owner of the organization that you won't be taking the job while stating your reasons respectfully. It might even lead to them offering better conditions in view of what you will say.A friend of mine had similar issue with an outfit that he applied for,and after he scale through the interview he was asked to resume,he keep postponing the resumption until he confided in me that he was in a at a fixed,i advise him to informed them that he would not like to take the job due to financial and logistics reasons.